President Barack Obama's forceful defense of the nuclear arms agreement with Iran clearly outlined the outcome if Congress rejects the deal.

War.

Perhaps it'll be conventional war, if other countries attempt to stop Iran by bombing its nuclear facilities. The more frightening image is of a nuclear arms race in an already deeply unstable region.

Take a moment and recall the photos of Hiroshima after the United States dropped the first atomic bomb 70 years ago today. More than 90,000 people were killed, and swaths of the Japanese city were destroyed. Three days later, the United States dropped its second bomb on the port city of Nagasaki, killing tens of thousands more.

While justification for the bombings is debated vehemently, their devastating impact -- from the cities destroyed to the radiation that poisoned generations -- is not disputed.

The world has to remember and learn and choose a path that might lead to a diplomatic solution in Iran -- and not the destructive alternative.

No one knows for sure whether the nuclear agreement will work or whether Iran will stick to its end of the deal. But there are several promising aspects, including the fact that relief from economic sanctions kicks in only after Iran reduces its centrifuges and uranium stockpile. And the sanctions are supposed to snap back if Iran violates the deal.

Without a deal, it's very possible that sanctions, particularly by Russia and China, won't hold. And it's unrealistic to expect that Iran would stop its nuclear program, including peaceful efforts to build power plants.

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As critics of the Iran deal raise objections, and Obama counters each, think beyond the rhetoric. Remember the four days in August 1945 when the use of nuclear weapons became real, and hold on to the hope that there's a way to move forward.

It's time to try a plan that might help us avoid repeating the horrors of our past. It's time to try to give our children a future that might keep atomic bombs and nuclear war in the history books.